The present invention relates to illuminators for facilitating use of displays in low ambient light conditions and, more particularly, to a novel wedge illuminator with polarizing member for illuminating and enhancing the contrast ratio of reflective dichroic liquid crystal displays.
Reflective displays are often attractive for data presentation. However, in low ambient light conditions, such as at night, it is well-known that artificial light sources such as lamps and the like, must be utilized to provide illumination of the front of the display to obtain the reflected light patterns transmitting the desired information read-out. In applications where minimum space, in front of the display, is available for positioning light souces, front illuminators may utilize a wedge-shaped light-transmissive member guiding the light from the source to the front of the display by total internal reflection. Previous attempts to apply wedge illuminators to reflective dichroic liquid crystal displays (which displays are particularly desirable because of the relatively low power consumption thereof) have resulted in relatively low contrast ratios and relatively dim displays. It is desirable to provide wedge illuminators for reflective dichroic liquid crystal displays, wherein the brightness and contrast ratio of the display are relatively greater than presently possible.